package java67_17.jiekou.pc;

public class USBTest {

	public static void main(String[] args) {
		System.out.println("USB设备的电压是:" + USB.V);// static
		// USB.V = 12;//报错,说明他是final

		USB u = new USBFan("扬子");
		u.work();
		u.show();
	}

}
